Winemaking: Soup to Nuts, Grapes to Bottle
Viticulture, the process of growing wine grapes, has been raised from ancient art to a complex combination of science and art. Add in all the other special knowledge and skills required to produce the end product —bottled wine— and you have a Herculean (or is that Dionysian?) task.
Vintners, makers of wine, have to consider site, season, soil and a host of other factors in order to deliver fine wine to the consumer’s table.
Dark soils absorb heat more efficiently and rocky soils allow better drainage and provide stones that also help retain heat. Relative concentrations of nitrogen and other elements play an essential part. Topography (the contours of land) partly determine the usable amounts of sunlight and shade, while climate encompasses temperature range, total sunlight available, annual rainfall, wind and so forth.
Which grapes are selected to be grown depend on the terroir. A ‘terroir’ is a group of vineyards (or even vines) from the same region that share similar soil type, weather conditions and other attributes. Planting time varies from late March to early April, with harvest ranging from late September to early October, depending on location, species and individual judgment.
Once harvested, usually by hand, the grapes are off to the crusher to be turned into must – skin, meat, and juice created in large vats containing a perforated, rotating drum. The holes allow juice and skins to pass through, but filter out stems.
Red-grape must is then sent to fermentation tanks, while white goes first to a wine press. The press is a large, usually stainless-steel cylindrical tank with an inflatable rubber bladder inside. The bladder is used to squeeze the skins against the tank walls to separate them from the juice. The result is sent to another fermentation tank.
Airtight fermentation tanks, holding anywhere from 1,500-3,000 gallons are cooled to around 40F (4C) and the vintner adds sugar and yeast to initiate the process. The yeast interacts with the glucose in the must through diffusion and a process called glycolysis occurs which produces other sugars and alcohol. This takes roughly 2-4 weeks, during which the vintner samples and measures the mixture.
Once fermentation is complete, red wines are sent to a press to filter the skins from what is now wine, then filtered again to remove the yeast. Some reds undergo a second, malolactic, fermentation process. White wines, by contrast, are allowed to settle, after which the yeast is filtered out.
With the yeast removed, the wines are stored in stainless steel tanks or oak barrels for anywhere between three months and three years.
After sufficient aging, where ‘sufficient’ is determined by individual judgment based on repeated taste and other tests, the wine is pumped from the tanks to a bottling machine. Most vineyards now have a highly automated bottling process, though even there labeling, foil addition, and stacking is often still done by hand.
Despite the many modern improvements to the winemaking process, most growers and winemakers still take a personal and passionate interest in selecting and tending vines, creating delicious varieties, and judging whether product meets their high standards. It’s easy to taste the results.